By way of example reference is made to document DE 100 65 824 A1, disclosing a stent for implantation in the ascending branch of the aorta. This prior art stent has a hollow cylindrical body which is open in the longitudinal direction for the passage of blood and which has a wall formed by a mesh structure. The body of the known stent is adapted to the anatomical shape of the aortic root and has a configuration widening in a concave shape. At its proximal end directed toward the heart, narrow fixing elements are distributed on the stent in the circumferential direction. At its distal end extending into the aortic arch, the body of the known stent is, as it were, cut off obliquely so that, on its circumferential area situated away from the vessels of the head in the implanted state, the stent has a greater longitudinal extent than it does on the opposite circumferential area. This means that the vessels of the head which branch off from the aortic arch are not covered by the stent.
The prior art stent has proven easy to implant in the area of the ascending aorta. Because of the completely different anatomical circumstances in the area of the descending aorta, however, a stent of this design cannot be used for treating aneurysms in the area of the descending aorta.
In cases of aneurysms of the thoracic aorta which may extend into the aortic arch, that is to say as far as the left subclavian artery (arteria subclavia sinistra), the problem is that the proximal fixing and sealing surface area available for the stents is not sufficient. In other words, the known stent cannot be sufficiently fixed in the aortic arch in the area opposite and proximal to the origin of the left subclavian artery.
In such a case, vascular surgery is therefore required prior to the intraluminal implantation of a vascular endoprosthesis, that is to say of a corresponding stent. Before the stent is implanted, a surgical vascular connection is created between the left subclavian artery and the common carotid artery branching off from the aortic arch proximal to the left subclavian artery, such that the subclavian artery is supplied as it were via the common carotid artery. The origin of the subclavian artery from the aortic arch can then be covered and closed off by a vascular endoprosthesis without any problem in order to ensure a sufficient surface area for fixing and sealing on the inside wall of the aorta.
Vascular surgery of this kind is very time-consuming and, in addition, the patient has to be linked up to a heart-lung machine and the body temperature of the patient has to be greatly reduced. For this reason, the mortality rate in interventions of this kind is very high.
A further disadvantage is to be seen in the fact that emergency management of a patient with an aneurysm of the thoracic aorta by insertion of a stent via a minimally invasive route has hitherto been virtually impossible, because sufficiently secure fixing of the proximal end of the stent entails problems.